Currently, there are various backplane technologies in a display industry, such as a-Si, LTPS, Oxide and so on, where: the a-Si is easily manufactured, but its mobility is low and its stability is not ideal; the LTPS has good stability, but a cost of the LTPS is high, uniformity of the LTPS is poor, and the LTPS is not suitable for manufacture of a panel with a large size. IGZO (indium zinc gallium oxide) is widely used in an OLED product with a large size due to its high mobility, good uniformity and low cost.
Luminescence uniformity of AMOLED is affected by a threshold voltage Vth, and in pixel design, a circuit for compensating the Vth may be added.
Pulses need to be added for internal compensation of a Scan signal, so as to extend a time of resetting and obtaining the value of Vth.
A traditional method adopts a peripheral IC design, which is not beneficial for a narrow frame and low cost.
Compensation periods of different panels are different, and so the number of pulses in the Scan signal is not fixed.